Self-consumption and battery size calculator
Pick your household profile and see how much of your solar electricity you would use yourself, with and without a battery, and whether the battery pays for itself.
Data set
These are reference values for Europe. Our country sites carry verified local data: myosolar.de, myosolar.at, myosolar.ch, myosolar.it, myosolar.es, myosolar.fr
Your inputs
Seeded from the household profile. Overwrite it with the figure from your bill.
kWp
Recommended usable capacity: 5.0 kWh
PVGIS was not reachable, so this result uses the market average yield and is an estimate rather than a location specific calculation.
Result
covers around 90.5% of your electricity demand
At these prices the battery pays back within its expected service life.
Your inputs are kept in the address of this page, so you can bookmark or share this result.
Assumptions and sources
The market data behind the calculation above, with source, date and quality, followed by the modelling assumptions the result depends on.
Change our assumptions
These are estimates for your market. Enter your real rates and every result recalculates immediately.
Market data with sources
- Household electricity price0.2896 EUR/kWh
European reference value. Choose your country site for local figures.
- Feed-in remuneration0.08 EUR/kWh
Illustrative only. Never print in an article. Use the market specific constant instead.
- Specific yield1,100 kWh/kWp
Illustrative only. Never print in an article. Use the market specific constant instead.
- Battery cost per kWh, lower end400 EUR/kWh
- Battery cost per kWh, upper end900 EUR/kWh
Modelling assumptions
These are modelling choices, not measurements. They shape the result, so we name each one and what it does to it.
- Self-consumption share12 to 90 percent, derived
We derive the share of your production that you use yourself from the ratio of annual production to annual consumption: the larger the system compared with your demand, the smaller the share. A battery raises it, in proportion to how much of a day of consumption it can store. A higher share raises the saving, because power used at home avoids the full electricity price.
- Annual operating cost1% of the investment
Insurance, metering, cleaning and repairs. Subtracted from the benefit every year, so it moves the payback date later.
- Module degradation0.5% per year
Panels lose a little output each year, so the annual benefit falls slowly across the projection.
- Electricity price increase2% per year
Assumed rise in the price of grid electricity. Every kilowatt-hour used at home is worth more over time, which shortens the payback.
- Projection horizon25 years
Cash flows are added up over this many years. Nothing beyond it is counted.
Rules that apply in your market
- These figures are European reference values, not the rules of a single country. Our country sites carry verified local data.
Frequently asked questions
- How large should a home battery be?
- As a rule of thumb, around one usable kWh per 1000 kWh of annual consumption. Larger batteries raise self-consumption only slightly while adding full cost.
- Does a battery make sense with a heat pump?
- Often yes, because a heat pump raises consumption in the evening and at night. The winter heating peak, however, cannot be covered by a small home battery.
- How long does a battery last?
- Current lithium systems are usually warranted for ten years or a defined number of cycles. Ask for the guaranteed remaining capacity at the end of the warranty.
Related tools
- Solar savings and payback calculatorSystem size, production, savings and payback for your market.
- Feed-in versus self-consumption calculatorHow the balance between using and selling your electricity moves the result.
- Wallbox and EV charging cost calculatorCharging cost from the grid and from your own roof, per year and per 100 km.
Matching guides
This is a transparent model for orientation, not an offer, not a yield guarantee and not financial advice. Binding figures need a site survey.